Vertical Storage Vessel

ABSTRACT

A vessel for containing liquefied petroleum gas and a method for loading a semitrailer with a plurality of vessels is disclosed. The vessel may include a tank with an outside diameter that is greater than thirty inches and less than thirty-four inches. The tank may be configured to contain at least 119 water gallons, and may be further configured to contain liquefied petroleum gas.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser.No. 60/911,791, filed Apr. 13, 2007, entitled Vertical Storage Vessel,which is hereby incorporated by reference.

TECHNICAL FIELD OF THE INVENTION

The present disclosure is related to storage vessels and moreparticularly, to vertical storage vessel systems and methods forexample, for storing liquefied petroleum gas (“LPG”).

BACKGROUND OF THE INVENTION

Storage vessels or tanks are used to store volatile liquids and gases.For example, LPG tanks are often used to contain liquefied petroleum gassuch as propane. LPG tanks come in a variety of sizes and are used inboth commercial and residential applications. LPG tanks are often usedin residential applications to provide fuel for fireplaces, stoves, anddryers. LPG tanks may be used in commercial application to provide fuelto heat a building.

To get an LPG tank from the manufacturer to a retailer or other userthat may fill the tank and offer it for sale, multiple LPG tanks may betransported on a semitrailer(s) having certain dimensions governed byfederal regulations.

SUMMARY OF THE INVENTION

The teachings of the present invention include a storage vessel that hasdimensions selected to increase the number of vessels that can betransported on a semitrailer. In accordance with a particular embodimentof the present invention, a vessel for containing liquefied petroleumgas includes a tank. The tank may have an outside diameter that isgreater than thirty inches and less than thirty-four inches. The tankmay be configured to contain at least 119 water gallons, and may befurther configured to contain liquefied petroleum gas.

In accordance with another embodiment of the present invention, a methodfor loading a semitrailer with vessels includes providing a plurality ofvessels. Each vessel may have an outside diameter that is greater thanthirty inches and less than thirty-four inches. Each vessel may beconfigured to contain at least 119 water gallons, and may be furtherconfigured to contain liquefied petroleum gas. At least thirteen stacksof vessels may be loaded on a semitrailer, wherein each stack comprisesnine vessels, and wherein an imaginary centerline of each vessel issubstantially horizontal.

Technical advantages of particular embodiments of the present inventioninclude an LPG tank that has the capacity to hold 119 water gallons andis sized to increase the number of tanks that may be loaded on asemitrailer for transport.

Further technical advantages of particular embodiments of the presentinvention include a tank that is relatively shorter and has a greaterouter diameter than a conventional LPG tank, that is still capable ofbeing used in conventional tank applications.

Still further technical advantages of the present invention include anLPG tank that is less than four feet tall, which is the standard heightfor the sill of a window in a residence. Therefore, an LPG tank inaccordance with the teachings of the present invention may be placed onthe outside of a residence near a window and not block a view out of thewindow.

Still further technical advantages of the present invention includevalve and fitting placement that may make fluid communication amongmultiple LPG tanks easier. Allowing fluid communication among LPG tanksmay substantially increase the quantity of available propane for certainapplications. Still further technical advantages of the presentinvention include an improved design of an LPG tank collar and lidinterface that may improve manufacturing and assembly.

Other technical advantages will be readily apparent to one of ordinaryskill in the art from the following figures, descriptions and claims.Moreover, while specific advantages have been enumerated above, variousembodiments may include all, some, or none of the enumerated advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present embodiments and advantagesthereof may be acquired by referring to the following description, takenin conjunction with accompanying drawings, in which like referencenumbers indicate like features, and wherein:

FIG. 1 is a schematic drawing of an embodiment of the present inventionhaving an illustration of a conventional LPG tank superimposed;

FIG. 2A is a schematic drawing of a side view of an LPG vessel inaccordance with an embodiment of the present invention;

FIG. 2B is a schematic drawing of a top view of an LPG vessel inaccordance with an embodiment of the present invention;

FIG. 2C is a schematic drawing showing the detail of a head to shellseam in accordance with an embodiment of the present invention;

FIG. 2D is a schematic drawing of an embodiment of the present inventionshowing a lid and collar interface in partially exploded view;

FIG. 3 is an illustration of an embodiment of the present inventionshowing a load layout of a semitrailer loaded with LPG vessels inaccordance with an embodiment of the present invention;

FIG. 4 is a schematic drawing of another embodiment of the presentinvention showing a second load layout of a semitrailer loaded with LPGvessels in accordance with an embodiment of the present invention;

FIG. 5 is a schematic drawing of an embodiment of the present inventionshowing an end view of a semitrailer loaded with LPG vessels inaccordance with an embodiment of the present invention;

FIG. 6 is a schematic drawing illustrating a detailed view of anembodiment of the present invention showing LPG vessels separated byprotective material; and

FIG. 7 is an illustration of a load layout of a semitrailer loaded with320 gallon LPG vessels in accordance with a further embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

The present disclosure is directed to a liquefied petroleum gas (“LPG”)tank assembly which may also be referred to as a vessel. Dimensions ofthe tank assembly may be selected to allow the tank to hold a certainquantity of liquid or pressurized gas while still allowing a maximumnumber of tanks to be transported on a semitrailer having length andwidth dimensions in compliance with United States federal sizeregulations for commercial vehicles.

FIG. 1 illustrates an improved LPG tank assembly 12 which may also bedescribed as a vertical storage vessel, a bottle, or a cylinder.Improved LPG tank assembly 12 is shown in FIG. 1 by solid lines.Superimposed over improved LPG tank 12 is conventional LPG tank 10,illustrated by broken lines on the drawing. Both improved LPG tank 12and conventional LPG tank 10 are capable of holding 119 water gallons.Improved LPG tank 12 is shorter and wider than conventional LPG tank 10.The outer diameter of conventional LPG tank 10 (OD₁) may be 30 incheswhile the outer diameter of improved LPG tank 12 (OD₂) may be 33 inches.In accordance with particular embodiments of the present invention, OD₂may be greater than 30 inches and less than or equal to 35 inches. OD₂may also be greater than 31 inches and less than 34 inches.

Conventional LPG tank 10 includes a domed lid 14 and a standard collar17. Improved LPG tank 12 also achieves reduced height for example, byreplacing domed lid 14 with flat lid 16 and replacing standard collar 17with shorter, improved collar 18.

By reducing the height of the collar, flattening the lid, and increasingthe outer diameter, improved LPG tank 12 may have an overall height(H₂). H₂ may be greater than or equal to 44 inches and less than orequal to 55 inches. In accordance with other embodiments of the presentinvention, H₂ may be greater than or equal to 44 inches and less than orequal to 48 inches. In accordance with particular embodiments of thepresent invention, H₂ may be equal to 44.085 inches. A reduced heightbase 19 may also contribute to reduced height H₂. Improved LPG tank 12achieves a significant reduction in height from height H₁ ofconventional LPG tank 10 which may be 55.375 inches to H₂, which may be44.085 inches, the difference being H₁−H₂ or 11.290 inches.

Consistent with the teachings of the present invention, LPG vessels ofvarious capacities may have reduced length and increased outer diametercompared to conventional tanks of the same capacity or volume. Forexample, LPG vessels that are capable of containing 320 water gallonsmay be made to have a reduced length of 84 and 3/16ths inches and anouter diameter of 33 inches. 400 water gallon LPG vessels may also havea 33 inch outer diameter consistent with the teachings of the presentinvention.

A 119 water gallon LPG vessel in accordance with the teaching of thepresent invention may have a volume or capacity in water gallons that isgreater than or equal to 3.4 and less than or equal to 3.9 times itsouter diameter in inches. It may also have a volume in gallons that isless than or equal to 3.8 and greater than or equal to 3.5 times itsouter diameter in inches. In accordance with a particular embodiment ofthe present invention, a 119 water gallon LPG vessel may have a volumeor capacity (119 gallons) that is 3.6 times the outer diameter of thevessel in inches. In addition, the volume or capacity in water gallons(119 water gallons) of an LPG vessel in accordance with the teachings ofthe present invention may be 2.7 times its height in inches.

In accordance with a particular embodiment of the present invention, a320 water gallon LPG vessel may have a volume or capacity in watergallons that is 3.8 times its length in inches.

In accordance with particular embodiments of the present invention, anLPG vessel may have a height in inches that is greater than or equal to1.33 and less than or equal to 1.67 times its outer diameter in inches.A particular embodiment of the present invention may have a height ininches that is equal to 1.45 times its outer diameter in inches.

FIG. 2A illustrates an LPG tank assembly or vessel 20 in accordance witha particular embodiment of the present invention. Tank assembly 20includes base 22, tank 32, lifting lug 26, and cover assembly 30. Acylindrical collar 34 is fixed to the top of tank 32 and includes twovisible access openings 35. Cylindrical collar 34 may surround valvesand fittings located at the top of tank 32. The valves and fittingsallow access to the contents of tank 32 and further allow tank 32 to befilled.

Lid 36 includes top surface 19 that is flat and generally perpendicularto an imaginary centerline 43 of tank 32 when lid 36 is in its closedposition. Being flat, top surface 19 of lid 36 decreases the overallheight E of LPG tank assembly or vessel 20. By decreasing the overallheight of LPG tank assembly 20, more tank assemblies 20 may fit on asemitrailer as shown in FIGS. 3 and 4. The height of cylindrical collar32 may be selected to allow cylindrical collar 32 to adequately protectthe valves and fittings and also to minimize the overall height of LPGtank assembly 20.

The outer diameter of tank 32 and LPG tank assembly 20 is designated inFIG. 2A as G. LPG tank assembly 20 may be a 119 gallon LPG tank. Outerdiameter G may be selected such that LPG tank assembly 20 is capable ofholding 119 water gallons and also selected to allow three tanks ontheir side and positioned generally tangent to each other on asemitrailer to maximize the surface of the semitrailer occupied by thevessels (see FIG. 5). In certain embodiments of the present invention,outer diameter G may be equal to 33 inches and overall height E may beequal to 44.085 inches Tank 32 includes shell ring 42, bottom head 38and top head 40. Shell ring 42 may be 0.192 inches thick and 22 incheslong (dimension C). It may also have longitudinal seam 44 created bywelding two lateral edges of shell ring 42 together with a full weld.Shell ring 42 may be fixed to top head 40 and bottom head 38 with a spotweld performed in accordance with UW-11(a) (5) (b). See FIG. 2C.

Bottom head 38 and top head 40 may each be a 2:1 elliptical head with a0.172 inch minimum thickness in accordance with ASME standards. Bottomhead 38 and top head 40 may also have thicknesses in accordance withU.S. Department of Transportation standards. Bottom head 38 and top head40 may have an outer diameter of 33 inches. Top head 40 may besubstantially similar to bottom head 38 with the exception that top head40 may have prepunched holes to receive couplings that will fit valvesand other fittings of tank assembly 20. Top head 40 and bottom head 38may have respective heights B and D of 8.340 inches.

LPG tank assembly 20 may be composed of material in accordance with ASMEstandards or may be material specified by U.S. Department ofTransportation regulations for portable cylinders. In accordance withASME standards governing pressure vessels, top head 40 and bottom head38 may be made of SA414G steel. Shell ring 42 may be made of SA455steel. A36 steel or equivalent may be the material for collar 34, base22, and lift lug 26. The couplings welded to top head 40 may be SA105steel. Collar 34 may have 3 tabs to facilitate welding to top head 40.Lid 36 may have a 16 inch outer diameter and may be made of C.Q. G-30galvanized carbon steel.

Reference number 46 indicates a reference line at the level of tankassembly 20 to which liquid would rise when the tank is 80% full.Dimension H shows 80% liquid level 46 being 10.1 inches below the top ofcoupling 48. Cover assembly 30 may have an overall height of A, where Aequals 5.8125 inches. Base hole 50 may be aligned with lift lug 26.

FIG. 2B illustrates a top view of tank assembly 20. The location of thevalve couplings are visible from FIG. 2B. Valve couplings are located onarcs I and K. Arc I may have a radius of 3.250 inches, and arc K mayhave a radius of 4.298 inches. Valve coupling 64 and valve coupling 68are located on arc I. Valve couplings 66 and 70 are located on arc K.This configuration allows valve couplings 70, 68, and 66 to besubstantially in a straight line.

Valve couplings 64, 66, 68, and 70 may be a 3000# half coupling and maybe three quarters of an inch, one inch, or one and one quarter inches indiameter. Valve coupling 64 may be capable of receiving a fill valve.Valve coupling may be capable of receiving a relief valve, and valvecoupling 68 may be capable of receiving a service valve. Coupling 70 maybe capable of receiving a float gauge.

The specific location of valve couplings 64, 66, 68, and 70 may allow aT-block to be coupled to a service valve secured to valve coupling 68.This T-block may allow multiple LPG tank assemblies to be coupled toeach other through a conduit that is received by the T-block throughcollar 34 at a access opening 35. This may allow multiple tankassemblies to be coupled together while lid 36 remains in a closedposition. By coupling multiple tanks, available propane is increased to240 gallon capacity or more without having to install a larger capacitytank.

Lid stop 60 may be coupled to cover assembly 30 by cotter pin 62. Cotterpin 62 may be 4 inches long. See FIG. 2D for more detail. Valvecouplings 64, 66, 68, and 70 may be located at angles designated by J,L, M, and N, where J equals 15 degrees, L equals 30 degrees, M equals 19degrees, and N equals 11 degrees.

FIG. 2C illustrates a detail of the seam where top or bottom head 38 or40 may be welded to shell 42. Dimension N equals approximately 13/16inches, and dimension O equals a minimum flat portion of 1 and ½ timesthe thickness of the steel. The seam shown may be created by inaccordance with ASME standards by a spot x-ray per UW-11 (a) (5) (b)with a weld re-enforcement inside and outside of ⅛th of an inch. Theseam may also be created in compliance with U.S. Department ofTransportation regulations governing portable cylinders.

FIG. 2D illustrates an isometric view of the coupling between lid 36 andcollar 34. Two collar tabs 82 each may have an aperture to receivecotter pin 62. Two corresponding lid tabs 86 each may also include anaperture 84 to receive cotter pin 62.

Collar tabs 82 may be formed by a multi-stage die as opposed to beingwelded to collar 34. A first stage of a multi-stage die may form thebasic features of collar 34. A second stage may form collar tabs 82 byremoving material to create tab apertures 92 and the shape of collartabs 82. A third stage of a multi-stage die may bend collar tabs 82approximately 90 degrees such that they are in the position shown byFIG. 2D.

Similar to the formation of collar tabs 82, lid tabs 86 may also beformed by a multi-stage die. A first stage of a multi-stage dye may formthe basic shape of lid 36. A second stage may remove material to formthe shape of lid tabs 86 and apertures 84. A third stage may bend lidtabs 86 approximately 90 degrees to the position shown in FIG. 2D.

Collar tabs 82 may be spaced 3 inches apart and lid tabs 86 may bespaced 3.17 inches apart. Coupling lid 36 to collar 34 may beaccomplished by aligning collar apertures 92 with lid apertures 84 andinserting cotter pin 90 through the four apertures. In accordance with aparticular embodiment of the present invention, lid stop 60 may beformed and function in accordance with the teachings of U.S. patentapplication Ser. No. 11/563,992, which is hereby incorporated byreference as if fully set forth herein, and be inserted between collartabs 82. Cotter pin 62 may couple lid 36, lid stop 60, and collar 34.

Tank assembly 20 may conform to the ASME code for pressure vessels,Section VIII, Division I or U.S. Department of Transportationregulations governing portable cylinders, NFPA 58. In compliance withASME standards, the maximum allowable working pressure may be 250 PSIGat 125 degrees Fahrenheit. The minimum design metal temperature (“MDMT”)may be −20 degrees Fahrenheit at 250 PSIG. The hydrostatic test pressureof tank assembly 20 and the maximum allowable stress of top head 40,bottom head 38, and shell ring 42 may be in compliance with ASME or DOTstandards. The weight of tank assembly 20 including the valve fittingsmay be approximately 320 pounds. The outside surface area may be 35square feet, and the relief capacity required for LPG may be 990standard cubic feet per minute.

FIGS. 3 and 5 illustrate an embodiment of the present invention. FIG. 3is a side view of semitrailer 110 loaded with tank assemblies or vesselsin accordance with an embodiment of the present invention. The tankassemblies or vessels may be 119 water gallon vessels. FIG. 5 is an endview of loaded semitrailer 110.

As shown in FIG. 3, loaded semitrailer 110 includes trailer bed 112.Trailer bed 112 may have a length R and a width W. Length R may be 48feet and width W may be 102 inches. Length T and width W may be requiredto comply with federal size regulations for commercial motor vehicles,and thus may have particular length and width requirements. Multiple LPGtank assemblies 100 are shown on trailer bed 112. In accordance with aparticular embodiment of the present invention, LPG tank assembly 100may have height Q and outer diameter Y (see FIG. 5) that allow a maximumnumber of LPG tank assemblies 100 to be loaded and transported ontrailer bed 112.

LPG tank assemblies 100 may be positioned on trailer bed 112 in groupsof nine. As shown in FIG. 5, three LPG tanks 20 may be positionedsubstantially tangent to each other while laying on their sides. Threetank assemblies 100 may rest on shipping timbers 114. When tanks 100 arepositioned substantially tangent to each other, they may occupy anoverall tank width X. X may equal 8 feet 3 inches (99 inches) . Shippingtimbers 114 may be 1 and 11/16ths inches thick. The overall height ofloaded semitrailer 110 from the level of the ground to the top of thetank stacks is shown as dimension U. Height U may be selected to be lessthan certain state regulations governing the maximum height of a loadcarried by commercial motor vehicles. This maximum height may be 13 feet6 inches. Dimension U may equal 12 foot 8 and ⅝ths inches.

In accordance with a particular embodiment of the present invention,between each tank 100 may be material to protect each tank fromcontacting another tank and thereby damaging it. Protective material118, shown in FIG. 6, may be padding, web strapping, or compressed foam.Protective material 118 may be selected and/or positioned so as to notsignificantly increase overall tank width X over 99 inches. Overall tankwidth X may be equal to or greater than 99 inches and less than or equalto 102 inches.

Shipping timbers 114 may be placed on top of three tank assemblies 100to allow three more tank assemblies 100 to be stacked on top thereof. Astack of tank assemblies 100 may comprise nine tank assemblies createdby stacking three sets of three tank assemblies on top of each other.The outer diameter of tank assembly 100, Y, may be selected such that itis less than trailer width W divided by three.

Each stack of nine tank assemblies 100 may be loaded onto trailer bed112 for transport. The overall height Q of tank assembly 100 may beselected such that it is less than trailer length R divided by thirteen.Q may be 44.085 inches. This may allow thirteen stacks of nine tankassemblies 100 (117 tank assemblies) to be loaded and safely transportedon trailer bed 112. The overall length of thirteen stacks of nine tankassemblies, 13Q, may be 47.76 feet. (44.085 inches×13). Each stack ofnine tank assemblies 100 may be positioned on trailer bed 112 such thateach tank assembly's imaginary center axis 106 is generally parallel totrailer bed 112. Each stack of nine tank assemblies 100 may bepositioned such that base 102 of a tank assembly of a first stack isdirectly adjacent and nearly contacts a lid of a tank assembly 100 in anadjacent stack.

Another embodiment of the present invention is illustrated in FIG. 4.Trailer bed 112 may be capable of transporting fourteen stacks of ninetank assemblies 100 with the aid of an extension to trailer bed 112. Theextension 116 to trailer bed 112 may be approximately 1 foot 3 and13/16ths inches long. In addition to extension 116, a stack of ninetanks may extend approximately 1 foot 2 inches beyond the length of thetrailer bed 112. This extension is shown by dimension S.

In accordance with a particular embodiment of the present invention, 126tanks may be transported with one trailer load. The overall length ofthe fourteen stacks of tank assemblies may be 14Q. 14Q may equal 51 feetand 3 and ¾ths inches.

FIG. 7 illustrates a further embodiment of the present invention. FIG. 7shows stacks of 320 gallon tank assemblies or vessels 130 loaded onsemitrailer 132. Each 320 gallon tank 130 may have an overall lengthdimension Z of 84 and 3/16ths inches, and an overall radius BB of 33inches. The overall length of six stacks of nine 320 gallon tanks may beshown by dimension 6Z. 6Z may be less than semitrailer length R, whichis 48 feet. 6Z may be equal to 42.094 feet. FIG. 7 illustrates a sideview of a 320 gallon tank load that is similar to FIG. 3 illustration ofa 119 gallon tank load. Thus, each stack showing three tanks 130 on topof each other from a side view represents nine tanks positioned similarto the configuration shown in FIG. 5.

Accordingly, FIG. 7 depicts fifty-four 320 gallon vessels as they mightbe loaded on semitrailer 122. Conventionally sized 320 gallon tankswould require that less than fifty-four be transported on a 48 footsemitrailer that complies with federal size regulations for commercialmotor vehicles. Conventional 320 gallon tanks may be transported inloads of 45 tanks. The teachings of the present invention may also beused for a 400 gallon tank assembly with a 33 inch outer diameter and areduced length.

Although the present invention has been described in severalembodiments, a myriad of changes and modifications may be suggested toone skilled in the art, and it is intended that the present inventionencompass such changes and modifications as fall within the scope of thepresent appended claims.

1. A vessel for containing liquefied petroleum gas, comprising: a tankhaving an outside diameter that is greater than thirty inches and lessthan thirty-four inches, the tank being configured to contain at least119 water gallons, and being further configured to store liquefiedpetroleum gas.
 2. The vessel of claim 1, wherein the tank has an outsidediameter of thirty-three inches.
 3. The vessel of claim 1, wherein thevessel has an overall length that is no greater than four feet.
 4. Thevessel of claim 1, wherein the tank is configured to contain a quantityof water gallons that is at least 2.7 times an overall length of thevessel in inches.
 5. The vessel of claim 1, further comprising: a collarcoupled to a top portion of the tank; and a lid coupled to the collar.6. The vessel of claim 5, wherein the lid comprises a top surface thatis substantially perpendicular to an imaginary longitudinal centerlineof the tank, when the lid is in a closed position.
 7. The vessel ofclaim 5, wherein: the collar comprises a collar hinge portion, thecollar hinge portion and the collar being fabricated from a single pieceof sheet metal; and the lid comprises a lid hinge portion, the lid hingeportion and the lid being fabricated from a single piece of sheet metal.8. The vessel of claim 1, wherein the vessel complies with AmericanSociety of Mechanical Engineers standards for pressure vessels.
 9. Thevessel of claim 1, wherein the vessel complies with United StatesDepartment of Transportation regulations for portable cylinders.
 10. Thevessel of claim 1, further comprising: a plurality of valves wherein atleast three valves of the plurality of valves are substantially alignedin a straight line.
 11. The vessel of claim 1, wherein the tank isconfigured to contain at least 320 water gallons.
 12. The vessel ofclaim 11, wherein the tank is configured to contain at least 400 watergallons.
 13. A method of loading a semitrailer with vessels, comprising:providing a plurality of vessels, each vessel having an outside diameterthat is greater than thirty inches and less than thirty-four inches,each vessel being configured to contain at least 119 water gallons, andbeing further configured to contain liquefied petroleum gas; loading atleast thirteen stacks of vessels on a semitrailer, wherein each stackcomprises nine vessels, and wherein an imaginary centerline of eachvessel is substantially horizontal.
 14. The method of claim 13, furthercomprising: unloading the at least thirteen stacks of vessels from thesemitrailer.
 15. The method of claim 13, wherein each vessel isseparated from an adjacent vessel by protective material.
 16. A methodof loading a semitrailer with vessels, comprising: providing a pluralityof vessels, each vessel having an outside diameter that is greater thanthirty inches and less than thirty-four inches, each vessel beingconfigured to contain at least 320 water gallons, and being furtherconfigured to contain liquefied petroleum gas; loading at least sixstacks of vessels on a semitrailer, wherein each stack comprises ninevessels, and wherein an imaginary centerline of each vessel issubstantially horizontal.
 17. The method of claim 16, furthercomprising: unloading the at least six stacks of vessels from thesemitrailer.
 18. The method of claim 16, wherein each vessel isseparated from an adjacent vessel by protective material.